Just Ask the Expert: What's causing this dog's sudden blindness and polyphagia? - Veterinary Medicine
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Just Ask the Expert: What's causing this dog's sudden blindness and polyphagia?

CASE OUTCOME

After testing revealed a normal blood pressure, Alice was evaluated by an ophthalmologist, and SARDS was diagnosed. Female dogs may be more likely to develop SARDS, and, despite normal serum chemistry profile results, all dogs with SARDS should be specifically tested for Cushing's disease. Owners of dogs with SARDS frequently report concurrent onset polyuria and polydipsia.

Clinically, SARDS is characterized by a loss of vision over one to two weeks. The retina appears normal at first but will degenerate over time. SARDS can be detected by chromatic pupillary light activity testing. Dogs with SARDS will have no response to red light and good response to blue light.1 A definitive diagnosis of SARDS should be established by electroretinography.

The cause of SARDS remains undiscovered, but one study says that SARDS may be a paraneoplastic syndrome,2 and there are other reports of some SARDS patients responding to intravenous immunoglobulin G (IVIg), thus raising suspicions for an immune-mediated process.3 Currently, there is no approved treatment for SARDS.

Christopher G. Byers, DVM, DACVECC, DACVIM
VCA Veterinary Referral Associates
500 Perry Parkway
Gaithersburg, MD 20877

REFERENCES

1. Grozdanic SD, Matic M, Sakaguchi DS, et al. Evaluation of retinal status using chromatic pupil light reflex activity in healthy and diseased canine eyes. Invest Ophthalmol Vis Sci 2007;48(11):5178-5183.

2. Gilmour MA, Cardenas MR, Blaik MA, et al. Evaluation of a comparative pathogenesis between cancer-associated retinopathy in humans and sudden acquired retinal degeneration syndrome in dogs via diagnostic imaging and western blot analysis. Am J Vet Res 2006;67(5):877-881.

3. Grozdanic SD, Harper MM, Kecova H. Antibody-mediated retinopathies in canine patients: mechanism, diagnosis, and treatment modalities. Vet Clin North Am Small Anim Pract 2008;38(2):361-387.

Answer provided by Christopher G. Byers, DVM, DACVECC, DACVIM, VCA Referral Associates, Gaithersburg, Md.


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Source: VETERINARY MEDICINE,
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